1. Field of the Invention
The present invention relates to an insert cutter having a plurality of indexable cutter inserts releasably attached to a peripheral surface of a tool body.
2. Prior Art
FIGS. 29 and 30 depict one conventional face milling cutter of the aforesaid type, which includes a tool body 2 having a plurality of pockets 5 formed in an outer peripheral surface 4 thereof in circumferentially equally spaced relation to one another and opening to a forward end face 3 thereof. An insert-receiving recess 6 is formed in that wall of each pocket facing in a direction of rotation of the tool body 2. An indexable cutter insert 7 formed of cemented carbide is disposed on the insert-receiving recess 6 with a support member 8 interposed therebetween, and the insert 7 and the support member 8 are releasably secured to the insert-receiving recess 6 by means of first and second wedge members 9a and 9b.
In the aforesaid cutter, it is indispensable to make equal the distances L each defined between the corner cutting edge 7a of a respective insert 7 and the end face 2a of the tool body in order to ensure superior machining precision. However, in practice, although inserts of an identical shape and size are employed, the distances L vary due to the manufacturing errors regarding the insert-receiving recesses 6 and the inserts 7. Therefore, the distances L must be adjusted when mounting the inserts 7. This adjustment has been conventionally conducted by preparing a plurality of support members 8 having recesses 10 and wall portions of different sizes and selecting appropriate support members among them.
More specifically, a plurality of support members 8 having wall portions of various lengths S are first prepared. The lengths S usually range from 6 micrometers to 8 micrometers. Thereafter, the support members 8 having the same length S are selected, and the insert 7 is attached to the insert-receiving recess 10 of each of the selected support members 8. Then, each support member 8 is received by a respective insert-receiving recess 6 with its end face 8a mated with the wall 6a of the recess 6. Subsequently, clamp screws 11 and 12 are inserted through the first and second wedge members 9a and 9b, respectively, and are tightened loosely to hold each insert 7 and support member 8 lightly. In this condition, one of the inserts 7 is selected as a reference insert 7m, and if the distance L for a prescribed insert 7 to be checked is smaller than that for the reference insert 7m, the support member 8 for the insert is replaced by a support member 8 having a greater length S. On the other hand, if the distance L is greater than that for the reference insert 7m, the support member 8 is replaced by a support member 8 having a smaller length S. Then, the distance L is measured again, and these procedures are repeated until the distances L for all of the inserts to be checked become equal to the distance L for the reference insert 7m. Finally, all of the inserts 7 and the support members 8 are firmly secured by means of the wedge members 9a and 9b, so that the adjustment of the axial run-out for the inserts 7 is completed.
However, since the inserts 7 and the support members 8 must be repeatedly removed and mounted, the above adjustment requires a prolonged time, so that the mounting operation of the inserts is not efficient.
In addition, inasmuch as many support members of various sizes must be prepared, the number of parts is increased, resulting in a laborious maintenance of parts and an increase of maintenance costs.